Vehicle headlamps require horizontal and vertical adjustment to meet U.S. government legal headlamp aiming regulations. The typical aiming arrangement for a vehicle headlamp is based on a three point adjustment system. The headlamp is mounted to a fixed portion or panel of the vehicle. A reflector housing of the headlamp unit is attached to the panel along three rod supports which mount the reflector housing away from the vehicle panel. The first rod provides a fixed pivotal point which typically contacts the reflector housing along a lower end. Along the top end of the reflector housing is an adjustable length rod support typically called a vertical adjuster which typically contacts the reflector housing along the reflector housing top end vertically aligned with the fixed pivotal point. A horizontal adjuster to adjust the reflector housing in a horizontal axis is typically elevationally aligned with the fixed pivotal point and displaced to an extreme left or right end of the fixed pivot point.
To make vertical adjustments, the vertical adjuster will be manipulated in or out, causing the reflector housing to tilt up or down. In a similar fashion, to make horizontal adjustment to the left or right, the horizontal adjuster will be moved in or out. For a more thorough review of the arrangements of various vertical and horizontal adjustments in the three point adjustment system, see U.S. Ser. No. 08/169,464 Nagengast et al, filed Dec. 20, 1993.
To minimize space requirements, especially for the horizontal adjusters, frequently a right angle gear drive is utilized so that an input shaft may be torqued in a region vertically upward from the remainder of the adjuster where it may be more conveniently reached, thereby allowing packaging design constraints in the vehicle which would not allow hand access immediately rearward of the horizontal adjuster.
Prior to the present invention, the overwhelming majority of all automotive vehicles placed the vertical and horizontal adjuster rods in general parallel alignment. Therefore, an adjustment, especially of the horizontal adjuster (which is typically further away from the pivot point than the vertical adjuster), may sometimes cause a slight bending of the adjuster screws. This bending is typically slight and acceptable for most applications.
However, due to design constraints partially due to styling but even more so driven by an effort to minimize packaging and weight in a vehicle to enhance the vehicle's environmental acceptability, certain adjusters must now be located in such a manner that the horizontal and vertical adjuster rods can no longer be parallel mounted with respect to one another. In the nonparallel mounting arrangement, binding becomes a greater potential problem.